Air treating apparatus



AIR TREATING APPARATUS Filed June 8-, 1946 2 Sheets-Sheet l FILTER COOLING COIL HEATING COIL 3 11% n 106 3 mmvroa v 1 Patented May 31, 1949 AIR TREATING APPARATUS Charles D. Graham, Oakwood, Ohio, asslgnor to General Motors Corporation, Dayton, Ohio, a

corporation of Delaware Application June 8, 1946, Serial No. 675,363

8 Claims.

This invention relates to refrigerating apparatus and more particularl to an improved system for conditioning and sterilizing air.

It is an object of this invention to provide a simple and inexpensive system for conditioning air for comfort purposes.

It has long been known that various air-borne diseases interfere greatly with ones comfort and productive effort and as a result of this knowledge various methods and apparatus have been used to destroy bacteria in the air with varying degrees of success. One of the most effective and practical ways of destroying air-borne bacteria is to introduce a glycol vapor into the air.

It is an object of this invention to provide an improved method and apparatus for vaporizing germicidal agents such as the glycols which have a high boiling point and which in the undiluted state are diflicult to vaporize except at objectionably high temperatures.

It is another object of this invention to eliminate the need for adding water as such to the heated glycol solution in a glycol vaporizing unit.

Another object of this invention is to provide an improved arrangement for injecting the glycol vapor or other germicidal agent into the conditioned air stream.

Still another object of this invention is to provide an improved control arrangement for the vaporizing apparatus.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of .the present invention is clearly shown.

In the drawings:

Fig. 1 of the drawing is a somewhat diagrammatic vertical sectional view showing a. self-contained air conditioning unit embodying features of my invention; and

Fig. 2 is a diagrammatic view, partly in section, showing an improved arrangement for injecting a germicidal vapor into a central type of air conditioning system; and

Fig. 3 is a vertical Sectional view, partly diagrammatic, showing a modified type of vaporizing I Thus, concentra-' tions of .005 mgm. of triethylene glycol per liter of air is very effective in destroying air-borne bacteria. At this concentration, the air remains odorless and is non-toxic.

Referring now to Fig. 1 of the drawing, reference numeral l0 designates a conventional enclosure within which there is mounted an air conditioning unit generally designated by the reference numeral I2. This unit comprises an outer casing I4 which is provided with a return air inlet IS, a fresh air inlet I8, and a conditioned air outlet 20 all arranged as shown. A blower 22 is mountedwithin the cabinet and serves to circulate air in over the filter 24, the cooling coil 26, and the heating coil 28 and to discharge the air out through the outlet 20 in accordance with well-known practice. The cooling coil may be supplied with a cooling medium from any convenient source such as a volatile refrigerant liquefying unit (not shown) which may be mounted either directly within the cabinet I! or at some remote location. The heating coil 2| is used for heating the air whenever heating is required and is adapted to be supplied with a heating medium from any convenient source (not shown).

In the lower portion of the cabinet 14 there is mounted an insulated vaporizer tank 30 which is adapted to contain a solution of water and glycol. (The term glycol is used throughout the specification and claims in its generic sense and is intended to include all of the glycols such as ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol.) A perforated steam supply pipe 32 is provided adjacent the bottom of the vaporizer tank 30 and is adapted to supply dry steam at a pressure such that its temperature is at least 10 above the desired liquid temperature in the vaporizer tank. Although liquid temperatures between 270 and 300 F. will cause satisfactory vaporization, other temperatures may be maintained. By increasing the operating temperatures the rate of evaporation for a given concentration is obviously increased and vice versa. The flow of steam to the perforated steam supply pipe 32 is controlled by means of a valve 36' which may be of the manually controlled type or which may be of the automatic type operable either in response to the temperature of the solution within the vaporizer tank, the degree of concentration of the solution within the vaporizer tank or the degree of concentration of glycol vapor within the conditioned space.

A steam heating coil 38 has also been provided within the vaporizer tank 30 for adding auxiliary heat to the solution at such times when the heat supplied by the steam released from the perforated steam supply pipe 32 is not sufllcient to vaporizean adequate supply of glycol. The flow of steam through the coil 20 is controlled by means of a valve 40 which is arranged as shown and which is controlled by the thermostat 42 disposed so as to respond to the temperature or the solution within the vaporizer tank 30. A conventional steam trap 44 is provided in the return line 46 as shown.

The vapor leaves the tank through the outlet 48 and is discharged directly into the inlet opening 50 of the blower 22 so as to be thoroughly mixed with the air before it leaves the fan chamber. By virtue of this arrangement, the blower serves to reduce the pressure within the tank 30 and, consequently, increases the rate of vaporization.

Since the boiling temperature of water is 212- F. and the boiling temperature of triethylene glycol is 548 F., it is obvious that the water in the solution will vaporize more rapidly than the triethylene glycol. The vapor leaving the tank 30 for a given setting of the controls may contain over 95% water vapor and the rest glycol vapor. It has been found that this percentage does not constitute a disadvantage since the glycol vapors are more eflective, at relative humidities ranging from 30 to 50%. Thus the water vapor or steam which is discharged into the main air stream serves a useful purpose.

The steam discharged into the solution in the tank 30 through the steam supply pipe 32 is relied upon for supplying the necessary makeup water to the solution within the tank 30. Since only a very small amount of gylcol is vaporized from time to time, it is apparent that very little gylcol need be supplied to the tank. A glycol supply tank 52 has been provided within the cabinet I4 as shown and serves as a storage reservoir from which glycol may be added to the solution in the tank 30. The glycol enters the tank 30 through the pipe 54 within which there is placed a control valve 56. The valve 56 may be a manually controlled valve or it may be an automatically controlled valve which serves to supply the proper amount of glycol solution to the varporizer-tank. Thus the valve 56 may be a time controlled valve adapted to allow a given amount of glycol to flow at predetermined time intervals or it may be a valve controlled in response to changes in temperature of the solution within the vaporizer tank or in response to the degree of concentration of glycol vapor within the conditioned space. It is apparent that the temperature within the vaporizer tank will be affected by the rate of vaporization which in turn depends in part upon the degree of concentration within the vaporizer tank.

In Fig. 2 of the drawing I have shown a modified arrangement for supplying glycol vapor in a central air conditioning system. Reference numeral '0 designates a building having a plurality of rooms such as 62 and 64. A conventional duct system 66 having an air conditioning chamber 08 is provided for supplying conditioned air to the rooms 62 and 64. A centrifugal blower II is provided adjacent the outlet of the conditioning chamber I58 for causing circulation of air through the duct system in accordance with established practice. Fresh air may be added from time to time through the damper controlled fresh air inlet 12. A conventional filter -I4, a cooling coil 1i, and a heating coil 18 are provided within the chamber 68. The supply of coolingmedium to the coolingcoils I0 from a source (not shown) is controlled by the valve 00 which in turn is controlled by the thermostat 82 located in the return air stream. The flow of heating medium to the coil 18 from a source (not shown) is controlled by the valve 84 which is similarly controlled by a thermostat 86. The thermostats 82 and 86 are arranged so as to cause cooling medium to flow through the coil I6 when the temperature of the return air exceeds a predetermined value and to cause a heating medium to flow through the coil I l when the temperature of the return air falls below a predetermined value indicating that heating is required.

Vaporized glycol is supplied to the conditioning chamber 68 by the vaporizing unit generally designated by the reference numeral 90. The construction and operation of the vaporizing unit 00 is the same as that of the vaporizer shown in Fig. 1 and, consequently, needs no further description. The same reference numerals have been used to designate the corresponding parts of the vaporizing apparatus shown in Figs. 1 and 2.

A slightly modified form of vaporizing unit has been shown in Fig. 3 of the drawing wherein reference numeral I00 designates a glycol supply tank within which there is disposed a steam pipe I02 through which live steam under pressure is supplied to the steam jet I04 disposed within the venturi-like nozzle I06. The construction is such that glycol, either in the undiluted form or in a diluted form, will be pulled up from the glycol supply in the bottom of the tank I00 through the feed line I08. The flow of steam through the jet I04 will serve to atomize and vaporize the glycol fed into the escaping steam. The flow of steam through the pipe I02 is controlled by the valve 0 which may be a manually controlled valve or an automatically controlled valve. Since the ratio of water vapor to glycol vapor may be very high for the reasons explained hereinabove, a larger portion or all of the glycol leaving the nozzle I06 will be vaporized by the hot steam leaving the nozzle I04. The unvaporized glycol, if any, will be highly atomized and will serve effectively to kill the air-borne bacteria carried by the air. Some or all of the atomized glycol entering the air stream will be vaporized by the air. Makeup solution may be added to the tank through the opening I I2.

Units of the type shown in Fig. 3 may be used for discharging glycol or other types of germicidal or deodorant materials directly into the conditioned space or they may be used in conjunction with air conditioning apparatus of the type shown in Figs. 1 and 2 in which case the nozzle I05 would preferably be arranged to discharge into the conditioned air stream ahead of the blower.

Whereas the apparatus disclosed herein is primarily designed for use in comfort air conditioning systems, it is obvious that the apparatus could be used in other types of installations.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. In an air conditioning system, the combination of a tank adapted to contain a germicidal solution, a steam pipe disposed within said tank below the liquid level therein for supplying heat to said solution, at least a portion of said pipe having perforations for allowing steam to escape from said pipe into said liquid solution so as to cause vaporization of said solution, and means for directing the resulting vapor into a space to be conditioned.

2. In combination with an enclosure, a cabinet within said enclosure, a vaporizer tank within said cabinet, a blower within said cabinet for circulating air for said enclosure through said cabinet, said vaporizer tank being adapted to contain a germicidal solution, means for heating said solution comprising a steam pipe having outlet means disposed below the liquid level of said solution so as to discharge steam into said solution, and means for directing vapor from said vaporizer tank into the inlet of said fan means.

3. In combination with an enclosure, a cabinet within said enclosure, a vaporizer tank within said cabinet, a blower within said cabinet for circulating air for said enclosure through said cabinet, said vaporizer tank adapted to contain a germicidal solution, means for heating said solution comprising a perforated steam pipe disposed below the liquid level of said solution, means for conducting steam under pressure to said pipe for discharge in said solution to vaporize said germicidal solution, means for directing vapor from said tank into the inlet of said fan means, and means within said cabinet for heating the air before said vapor is discharged into the air.

4. In combination with an enclosure, a cabinet within said enclosure, a vaporizer tank within said cabinet, a blower within said cabinet for circulating air for said enclosure through said cabinet, said vaporizer tank being adapted to contain triethylene glycol, means for heating and vaporizing said glycol comprising means for discharging steam into and below the level of said glycol in said tank, means for directing the glycol vapor into the inlet of said fan means, and means within said cabinet for cooling the air before said vapor is discharged into the air.

5. An air conditioning apparatus comprising in combination, means forming a chamber, blower means for circulating a stream of air through said chamber, means within said chamber for heating said stream of air, vaporizing means for generating triethylene glycol vapor, and means for conveying said triethylene glycol vapor from said vaporizing means to a point in said chamber ahead of said blower means.

6. An air conditioning apparatus comprising.

in combination, means forming a chamber, blower means for circulating a stream of air through said chamber, means within said chamber for heating said stream of air, vaporizing means for generating triethylene glycol vapor, and means for conveying said triethylene glycol vapor from said vaporizing means to a point in said chamber ahead of said blower means, said vaporizing means comprising means for mixing steam with the triethylene glycol vapor.

7. An air conditioning apparatus comprising in combination, means forming an air conditioning chamber, attemperating means within said chamber, blower means for circulating air through said chamber, and vaporizing means disposed within said chamber for supplying a germicidal medium in vapor form into the air flowing through said chamber before said air enters said blower means.

8. In an air conditioning system, means for circulating a stream of air to and from an enclosure, means for supplying a vapor into said stream of air comprising a tank adapted to contain a substance to be vaporized, means for discharging live steam directly into said substance so as to heat said substance and vaporize a portion thereof, and means for directing said vaporized portion together with any of said steam leaving saidsubstance into said stream of air.

CHARLES D. GRAHAM.

REFERENCES CETED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,926,579 Burgess et al Sept. 12, 1933 2,150,263 Chesney Mar. 14, 1939 2,234,400 Evans et al. Mar. 11, 1941 2,344,536 Coey et al Mar. 21, 1944 2,369,900 Jennings et al. Feb. 20, 1945 

